ILLUSTRATION of hantavirus testing concept with laboratory tubes containing cotton swabs and HANTAVIRUS labels photographed in front of a public domain hantavirus related microscopic image released by the US Centers for Disease Control and Prevention CDC in Paris, France, May 8 2026.

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Jenni Fink

By Jenni Fink

Senior Editor

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Health officials across the United States and around the world are monitoring a rare but deadly outbreak of hantavirus after multiple confirmed cases were linked to a luxury cruise ship, including possible patients who weren't ever on the ship.

While hantavirus's lethality is concerning, its weeks-long incubation period makes controlling cases and contact tracing difficult. But authorities are stressing that the overall risk to the general public remains extremely low, in part because hantavirus requires close, prolonged contact with another person to transmit between humans. Cases remain low, but new ones are being identified.

“At the moment, there is no sign that we are seeing the start of a larger outbreak,” World Health Organization (WHO) Director-General Dr. Tedros Adhanom Ghebreyesus said. "But of course the situation could change, and given the long incubation period of the virus, it’s possible we might see more cases in the coming weeks.”

Read More on U.S.

On Sunday, Canadian health officials confirmed a 10th case tied to the ship, this one in a patient living in British Columbia. A second person who was tested had a negative result, the Associated Press reported.

The outbreak centers on the MV Hondius, a Dutch‑flagged expedition cruise ship, where confirmed and suspected cases of hantavirus have been identified among passengers from multiple countries. At the same time, state health officials in Illinois are investigating a possible hantavirus infection in a Winnebago County resident, unrelated to the cruise ship and involving a different strain of the virus.

Hantavirus Case Map Live Tracker

U.S. health officials have expanded their monitoring efforts after identifying 16 additional travelers who may have been exposed to hantavirus during an April 25 flight to Johannesburg. These individuals were not connected to the cruise ship but shared a long‑haul flight with a passenger who was later confirmed to be infected, according to CDC response lead Dr. David Fitter. Their addition brings the total number of people under observation in the United States to 41.

Eighteen cruise passengers who were repatriated earlier this week remain in federal quarantine facilities in Omaha and Atlanta, while seven others who returned home on commercial flights are being followed by state health departments. Officials have not released details on where the newly identified passengers traveled after entering the country, and there are still no confirmed U.S. cases linked to the outbreak.

The CDC says monitoring remains precautionary, and those who may have been exposed are being urged to stay home and limit contact with others during a 42‑day observation period. Dr. Fitter said the agency is working to stay in contact with every American who might have been exposed, whether domestically or abroad, as investigators continue tracing the movements of the infected traveler who died shortly after arriving in Johannesburg.

The Public Health Agency of Canada confirmed the positive test a day after the public health officer for the province of British Columbia said the person had received a “presumptive positive” but further testing would be conducted at the National Microbiology Lab in Winnipeg, AP reported.

The WHO has emphasized that confirmed and suspected cases tied to the cruise ship have been among passengers or crew members, so there's no evidence of sustained community spread. However, a case in the United States has been identified that appears to have no connection to the ship.

Hantavirus Case Tracker

Hantavirus Case Tracker

Interactive map and case table showing confirmed, probable and suspected hantavirus infections as reports continue to emerge.

Data shown is compiled from publicly available reports and is subject to change. If the interactive does not load, you can view the tracker in full here .

Where Has Hantavirus Been Detected in the US?

In the United States, no widespread domestic outbreak has been confirmed, but multiple states are monitoring individuals who have been exposed to hantavirus or are exhibiting symptoms. Passengers from the ship returned to the United States after evacuating on May 10, and most are quarantining in Nebraska.

"[We] are concerned about the fact that there aren't vaccines or treatments," Nyka Alexander, team lead for emergencies communications of the WHO, said on Wednesday. She added that a group of experts is meeting to determine whether any monoclonal antibodies or treatments that haven't yet been proven effective should be studied.

Ten people are being monitored across five states because they were potentially exposed to the virus. None of them were on the ship, but had contact with someone who tested positive for the virus. None of the individuals is displaying symptoms, though, so they are not confirmed to have been infected. They're being monitored in:

California is monitoring two residents who are asymptomatic. One person, who lives in Santa Clara County, was a passenger on the MV Hondius and left before the outbreak was identified, and another person, who lives in Sacramento County, was exposed to someone who was on the ship while on a flight in South Africa.

Kansas is monitoring three people, who don't have symptoms, but were potentially exposed after having contact with someone who was on the cruise ship that tested positive. Maryland and New Jersey are each monitoring two people who were on a flight with an infected cruise ship passenger. Health officials in Washington also said they were monitoring two people who sat near a passenger from the cruise ship who tested positive for hantavirus.

In Arizona, a person who was on the ship is being monitored but is not symptomatic as of May 7. Two people who left the ship before the outbreak was confirmed are being monitored in Texas, and a person in Virginia is being monitored after leaving the ship, but is in good health. Two people are also being monitored in Georgia after they returned to the U.S. from the ship.

Illustration: A person holding a test tube labeled "HANTAVIRUS," photographed in front of a hantavirus-related microscopic image.

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The Illinois Department of Public Health (IDPH) is investigating a possible hantavirus case in Winnebago County, located near Rockford. Officials say the case is not linked to the MV Hondius outbreak and does not involve the Andes strain, which has been capable of limited person‑to‑person transmission in rare circumstances.

According to IDPH, the Illinois resident did not travel internationally and is believed to have been exposed while cleaning a home where rodent droppings were present. The individual experienced mild symptoms, did not require hospitalization, and is recovering. The Centers for Disease Control and Prevention (CDC) is conducting confirmatory testing, which can take up to 10 days to complete.

Hantavirus has appeared in nearly every U.S. state, but 94% of all confirmed cases since 1993 have occurred west of the Mississippi, with the Four Corners region remaining the most affected. The 2026 outbreak investigations expanded monitoring into 16 states, even though no U.S. cases have been confirmed this year.

What Is Hantavirus?

Hantavirus is a family of viruses most commonly transmitted to humans through contact with infected rodent urine, feces or saliva, often when contaminated dust becomes airborne and is inhaled.

In the United States, most hantavirus infections are associated with exposure to rodent droppings in enclosed or poorly ventilated spaces, such as cabins, barns or homes. The virus is rare but can cause a severe and potentially fatal illness known as Hantavirus Pulmonary Syndrome (HPS).

Health officials stress that most North American strains of hantavirus do not spread from person to person, which is a key reason experts say the current risk to the general public remains low.

However, the Andes strain, which is believed to be responsible for the cruise ship outbreak, is unique. It is the only known hantavirus strain capable of limited human‑to‑human transmission, typically occurring during prolonged close contact with an infected person, according to the CDC and WHO.

Hantavirus Symptoms

Hantavirus symptoms often begin with flu‑like signs but can rapidly progress to life‑threatening respiratory illness.

Early symptoms commonly include:

Some patients later develop a sudden and severe respiratory phase, marked by shortness of breath as fluid builds up in the lungs. This stage can require intensive medical care, including mechanical ventilation and advanced life‑support measures.

A critically ill French woman who was infected on the cruise ship is on life support and being treated with an artificial lung. The hope is that the device can relieve enough pressure on her lungs and heart for her to recover, Dr. Xavier Lescure, an infectious disease specialist at Bichat Hospital, told the Associated Press.

Doctors note that because symptoms can worsen quickly, anyone who develops flu‑like illness after known rodent exposure or contact with a confirmed case should seek medical attention immediately.

The CDC and WHO have repeatedly emphasized that the situation is not comparable to COVID‑19 and does not currently pose a pandemic threat. While more cases linked to the cruise ship may still emerge due to the virus’s long incubation period, officials say there is no sign of sustained, widespread transmission.

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